The New York Times reports on the interesting information being revealed in the first DePuy ASR hip trial:
Separately, a DePuy engineer, Graham Isaac, testified on Thursday that before selling the A.S.R., the company only tested its performance on laboratory equipment at one angle of implantation.
Depending on the surgical technique and a patient’s build, orthopedic surgeons can implant the cup component of an artificial hip at a variety of angles. And because the A.S.R. had a design flaw, normal variance from the single angle at which DePuy had tested it made it more likely for the joint’s cup and ball components to strike each other, releasing metallic debris inside a patient.
Source: Hip Implant’s Risks Inadequately Assessed, DePuy Report Found in 2010 - NYTimes.com
Our sources tell us that the DePuy ASR implants are very likely to have been implanted at angles other than the one that was tested internally. Whether the fact that DePuy engineers only tested one angle was intentional or a coincidence is purely a matter of conjecture at this point.